Voicemail buttons get same blue selector as phone app.

- Requires that I change the rate change buttons, so that they extend to
  top and bottom of seek bar panel (otherwise it looks wrong when
  selected).
- Required putting the play and speakerphone button inside its own
  linear layout.

Bug: 5097940
Change-Id: I68acd9a9b13c7081cc1b346433d74333f6d79745